Case discussion

65 year male recently got bed restricted due to generalized weakness following anorexia and vomiting.

He has been using lithium carbonate for his manic-depressive illness for some 15 years.

On examination he is lethargic but able to communicate, Temp: 101f, pulse 124bpm and respiratory rate 16 /min. Blood pressure 100/60 lying and 70/40 on sitting.

Investigation: Lithium 1.5 mmole/lit;  Urea 20mg/dl and S. creatinine 1.3mg/dl. Na 169 ,  Ca 2.3mmole/l.

Glucose 4mmole; urine osmolality 240.

Give probable reason for patients hypernatremia, polyurea and polydipsia?

This patient has developed nephrogenic diabetes inspidus due to prolong use of lithium for his

Manic-depressive illness. Lithium block the action of ADH as well as adenylate cyclase in collecting duct

, thereby excessive water excretion or we can say decreased water absorption has led to increased serum osmolality and decreased urine osmolality. In this way thrist mechnism is stimulated to compensate increased serum osmolality.

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Common Drugs causing nephrogenic diabetes inspidus:

Lithirm

Amphotericin B

Demeclocycline

Polyurea with headache

29 year woman with 1 month history of headache , increased thrist and urinary frequency.
Urinary out put over 24 hours was 8 liters.Fluid deprivation test was performed with following
results:

 Time                              Serum Osm                  Urine Osm                    Serum ADH             Urine output

Baseline                           144                              80                                 2                                  -

1 hour                               147                             80                                  2                              600

2 hour                               150                              80                                  2                               500


Q.        What is the diagnosis?
Q.         Treatment?


Answere:    This patient has central diabetic inspidus and his defect seems to be severe.The D/D should include both central and nephrogenic dI, as well psychogenic polydipsia and diuretic use.

Desmopressin( Vasopressin) is the prefered teatment.








Vasopressin